Classics at Oxford

I don't think you should rule out Oxford at all, if you like the course content/structure and the tutorial system. @elilast is better-placed to advise about Classics applications though
It might be helpful to know what subjects you're taking in Sixth Form

i got 9988776665 at gcse (9s in lit/lang, ancient history at 8) (with 5 in business and 6s in maths, chem, phys) and I'm doing well in my alevels so far. should I rule out oxford realistically, and other Russell groups for that matter?

eng lit, classics and history!!

I don't think you should rule out Oxford at all, if you like the course content/structure and the tutorial system. @elilast is better-placed to advise about Classics applications though
It might be helpful to know what subjects you're taking in Sixth Form

Your GCSE grades will be viewed contextually, so if you have less than perfect grades but come from an average-performing school where you are one of the high achievers, that will be taken into account. On the other hand, if you got those grades from a selective school where most people get 7+ in all subjects then your grades may be more of a barrier.
Bear in mind Classics at Oxford is a very language heavy course. You have to feel enthusiastic about learning an ancient language to thrive on it.